Method and system for recovering and utilizing heat energy produced by computer hardware in blockchain mining operations

ABSTRACT

A method for recovering heat energy from computer hardware in a blockchain mining operation. The method may include the steps of providing heat energy that may be generated by computer hardware in a blockchain mining operation, and utilizing the heat energy in an absorption cooling module to generate a cooling effect with a coolant fluid. The coolant fluid may comprise a fluid refrigerant-absorbent mixture. The absorption cooling module may include an ammonia-water absorption refrigerator module, one or more heatsinks, a fluid pump, and a heat exchanger. The ammonia-water absorption refrigerator module may include a generator that may absorb heat energy adjacent to the generator. The one or more heatsinks may be positioned on the computer hardware. The fluid pump may be in fluid communication with the one or more heatsinks. The heat exchanger may be in fluid communication with the fluid pump and with the at least one heatsink.

RELATED APPLICATIONS

This application is a divisional application of and claims priorityunder 35 U.S.C. § 120 of U.S. patent application Ser. No. 16/278,080(Attorney Docket No. 4460.00011) filed on Feb. 16, 2019 and titledMethod And System For Recovering And Utilizing Heat Energy Produced ByComputer Hardware In Blockchain Mining Operations, which in turn claimspriority under 35 U.S.C. § 119(e) of U.S. Provisional Patent ApplicationSer. No. 62/631,691 filed on Feb. 17, 2018 and titled Heat EnergyTransfer. The contents of these applications are incorporated herein byreference except for where the disclosures therein conflict with thedisclosures herein.

FIELD OF THE INVENTION

The present invention relates to methods for recovering heat (i.e.,thermal) energy by computer hardware in blockchain (e.g.,cryptocurrency) mining operations and utilizing that recovered heatenergy in adsorption cooling modules which are an ammonia-wateradsorption refrigerator module and/or adsorption immersion coolingmodule. The present invention also broadly relates to a system forimplementing this method.

BACKGROUND OF THE INVENTION

Blockchain is an emerging technology of maintaining a public ledger in adecentralized computer network and is resistant to modification ofrecords. It is often associated with cryptocurrencies (such as bitcoin)but can also be applied to recording transactions of various othercategories (medical record, public records, etc.) in a verifiable andpermanent way. Similarly, it may also be used for improving security forthe “Internet of Things” (IoT) technologies.

The cornerstone of blockchain technology is the concept of the“proof-of-work” which relies on the heavy use of the computational powerto add records to the ledger and hence, make it falsification-proof.Thus, by design, adding records to the blockchain ledger requiressignificant amounts of computational work. The computational workrequired to support a blockchain ledger (for example, for a bitcoinnetwork) is known as “mining.” Mining is currently performed by clustersof specialized computer hardware known as “mining farms.” This computerhardware may include computer processing units (CPUs), commonly referredto as processors, graphic processing units (GPUs), field-programmablegate arrays (FPGAs), application-specific integrated circuits (ASICs),etc. One difference between GPUs and ASICs used in mining farms is thatASICs are much faster while GPUs are moderately flexible. ASICs are alsomore expensive and may be limited to a narrower set of functions. Bycontrast, GPU's perform operations by acting as accelerators forparallel-working algorithms.

This background information is provided to reveal information believedby the applicant to be of possible relevance to the present invention.No admission is necessarily intended, nor should be construed, that anyof the preceding information constitutes prior art against the presentinvention.

SUMMARY OF THE INVENTION

With the above in mind, embodiments of the present invention are relatedto a method for recovering heat energy from computer hardware in ablockchain mining operation. The method may include steps of providingheat energy that may be generated by computer hardware in a blockchainmining operation, and utilizing the heat energy in an absorption coolingmodule to generate a cooling effect with a coolant fluid. The coolantfluid may comprise a fluid refrigerant-absorbent mixture.

The absorption cooling module may include an ammonia-water absorptionrefrigerator module, one or more heatsinks, a fluid pump, and a heatexchanger. The ammonia-water absorption refrigerator module may includea generator that may be configured to absorb heat energy adjacent to thegenerator. The one or more heatsinks may be positioned on the computerhardware. The fluid pump may be in fluid communication with the one ormore heatsinks. The heat exchanger may be in fluid communication withthe fluid pump and with the at least one heatsink.

At least a portion of the heat exchanger may be adjacent to thegenerator. The fluid pump may circulate a heat transfer fluid to andfrom the one or more heatsinks and the heat exchanger. The heat transferfluid may absorb heat energy from the one or more heatsinks and from thecomputer hardware. The generator may absorb heat energy from the heatexchanger and from the heat transfer fluid. The blockchain miningoperation may comprise a cryptocurrency mining operation and/or a miningfarm.

The fluid refrigerant-absorbent mixture may comprise ammonia as therefrigerant and may comprise water and/or a fluoride salt as theabsorbent. The absorbent of the fluid refrigerant-absorbent mixture maycomprise functionalized graphene oxide nanoplatelets. The functionalizedgraphene oxide nanoplatelets may have one or more polaroxygen-containing functional groups including carboxyl, hydroxyl,carbonyl, and/or epoxy. The functionalized graphene oxide nanoplateletsmay be modified to have one or more alkyl substituent groups that mayhave a chain length of from 7 to 14 carbon atoms.

The computer hardware may comprise one or more printed circuit boards(PCB). The at least one or more heatsinks may comprise a thermallyconductive foil that may be mounted to the computer hardware bythermally conductive adhesive. The thermally conductive foil maycomprise graphene nanoplatelets. The thermally conductive foil may havea lateral thermal conductivity range of from about 1300 to about 1500Watts per meter-Kelvin.

BRIEF DESCRIPTION OF THE DRAWINGS

Some embodiments of the present invention are illustrated as an exampleand are not limited by the figures of the accompanying drawings, inwhich like references may indicate similar elements.

FIG. 1 schematically illustrates generally the absorption cooling moduleused in embodiments of the method and system of the present invention.

FIG. 2 schematically illustrates an embodiment of the method and systemof the present invention wherein the absorption cooling module is anammonia-water absorption refrigerator module.

FIG. 3 schematically illustrates an embodiment of the method and systemof the present invention wherein the absorption cooling module is anabsorption immersion cooling module.

DETAILED DESCRIPTION OF THE INVENTION

The present invention will now be described more fully hereinafter withreference to the accompanying drawings, in which preferred embodimentsof the invention are shown. This invention may, however, be embodied inmany different forms and should not be construed as limited to theembodiments set forth herein. Rather, these embodiments are provided sothat this disclosure will be thorough and complete, and will fullyconvey the scope of the invention to those skilled in the art. Those ofordinary skill in the art realize that the following descriptions of theembodiments of the present invention are illustrative and are notintended to be limiting in any way. Other embodiments of the presentinvention will readily suggest themselves to such skilled persons havingthe benefit of this disclosure. Like numbers refer to like elementsthroughout.

Although the following detailed description contains many specifics forthe purposes of illustration, anyone of ordinary skill in the art willappreciate that many variations and alterations to the following detailsare within the scope of the invention. Accordingly, the followingembodiments of the invention are set forth without any loss ofgenerality to, and without imposing limitations upon, the claimedinvention.

It is advantageous to define several terms before describing theinvention. It should be appreciated that the following definitions areused throughout this application.

Definitions

Where the definition of terms departs from the commonly used meaning ofthe term, applicant intends to utilize the definitions provided below,unless specifically indicated.

For the purposes of the present invention, the term “central processingunit” (used interchangeably with the term “CPU”) refers generally to theelectronic circuitry within a computer that carries out the instructionsof a computer program by performing the basic arithmetic, logical,control and input/output (I/O) operations specified by the instructions.The term “CPU” often refers to a processor, more specifically to itsprocessing unit and control unit (CU), distinguishing these coreelements of a computer from external components such as main memory andI/O circuitry.

For the purposes of the present invention, the term “graphics processingunit” (used interchangeably with the term “GPU”) refers generally to aspecialized electronic circuit designed to rapidly manipulate and altermemory to accelerate the creation of images in a frame buffer intendedfor output to a display device, and which may also be used for otherpurposes, operations, etc., (for example, in a blockchain operation).

For the purposes of the present invention, the term “field-programmablegate array” (used interchangeably with the term “FPGA”) generally refersto an integrated circuit designed to be configured by a customer or adesigner after manufacturing—hence the reference to“field-programmable.” An FPGA configuration is generally specified usinga hardware description language (HDL), similar to that used for anapplication-specific integrated circuit (ASIC).

For the purposes of the present invention, the term“application-specific integrated circuit” (used interchangeably with theterm “ASIC”) generally refers to an integrated circuit (IC) customizedfor a particular use, rather than intended for a general-purpose use.

For the purposes of the present invention, the term “blockchain” (alsoknown interchangeably as “block chain”) generally refers to acontinuously growing list of records, called “blocks,” which are linkedand secured using cryptography to form a distributed ledger. Each blocktypically contains a cryptographic hash of the previous block, atimestamp and a transaction data. By design, blockchain is inherentlyresistant to modification of the data. It may function as an open,distributed ledger that can record transactions between two partiesefficiently and in a verifiable and permanent way. For use as adistributed ledger, a blockchain is typically managed by a peer-to-peernetwork collectively adhering to a protocol for validating new blocks.Each succeeding block comprises a hash, a unique digital fingerprint, ofthe preceding one. Once recorded, the data in any given block cannot bealtered retroactively without the alteration of all subsequent blocks.

For the purposes of the present invention, the term “cryptocurrency”generally refers to a digital asset (also referred to as a “digitalcurrency,” “alternate currency,” virtual currency,” etc.) designed towork as a medium of exchange that uses cryptography to secure itstransactions, to control the creation of additional units, and to verifythe transfer of assets.

For the purposes of the present invention, the term “bitcoin” generallyrefers to a cryptocurrency and worldwide payment system involvingdecentralized digital currency using a peer-to-peer network (“bitcoinnetwork”) where transactions take place between users directly andwithout an intermediary. These transactions are verified by networknodes through the use of cryptography and recorded in a publicdistributed ledger such as blockchain.

For the purposes of the present invention, the term “bitcoin network”generally refers to a peer-to-peer payment network that operates on acryptographic protocol involving bitcoins. Users send and receivebitcoins, the units of currency, by, for example, broadcasting digitallysigned messages to the network using bitcoin cryptocurrency walletsoftware. Transactions are recorded into a distributed, replicatedpublic database such as blockchain, with consensus achieved by aproof-of-work system such as mining.

For the purposes of the present invention, the term “mining” generallyrefers to the computational work performed in a proof-of-work system tosupport a cryptocurrency “peer-to-peer” network such as blockchain or abitcoin network.

For the purposes of the present invention, the term “mining farm” refersto one or more clusters of specialized computer hardware used to carryout mining.

For the purposes of the present invention, the term “computer hardware”refers to the physical components of a computer, such as the monitor,keyboard, computer data storage, graphic card, sound card, motherboard,heat sinks, etc.

For the purposes of the present invention, the term “components ofcomputer hardware” refers to those components of the computer hardwarethat generate heat energy or are involved in conducting heat energy,such as the central processing unit (CPU); circuit boards, such asprinted circuit boards (also known interchangeably as “PCBs”); chipsets;memory chips such as random-access memory (e.g., RAM, SRAM, DRAM, etc.),read-only memory (ROM, etc.); buses; graphic cards; video cards; datastorage disks, such as hard disks; etc.

For the purposes of the present invention, the term “coolant fluid”refers to a composition, mixture, suspension, solution, etc., which isfluid (e.g., liquid), can extract, remove, conduct, absorb, etc., heatenergy, and can then release the extracted, removed, conducted,absorbed, etc., heat energy to cause, impart, etc., a cooling effect.Suitable coolant fluids for use herein are dielectric, and have aboiling or vaporization temperature within the range of normal operatingtemperatures of computer hardware used in a blockchain mining operation.

For the purposes of the present invention, the term “absorption coolingmodule” refers to a cooling module which employs a coolant fluid in theform of a fluid refrigerant-absorbent mixture. An absorption coolingmodule typically employs a combination of three phases: (1) anevaporation phase wherein the gaseous or liquid refrigerant evaporates(vaporizes) due to extracting heat from its surrounding lower pressureenvironment and producing, imparting, causing, etc., a cooling effect;(2) an absorption phase wherein the vaporized (gaseous) refrigerant fromthe evaporation phase is absorbed by an absorbent solution containing anabsorbent (e.g., a refrigerant-depleted absorbent solution from theregeneration phase) to form an refrigerant-enriched absorbent solution;and (3) a regeneration phase wherein the refrigerant-enriched absorbentsolution from the absorbent phase is again heated (e.g., in a generator)to vaporize the refrigerant from the absorbent solution (thus forming arefrigerant-depleted absorbent solution), the vaporized refrigerant fromthe generator passing through a heat exchanger (e.g., a condenser) tocondense the refrigerant into a liquid form (to be returned to supplyrefrigerant for the evaporation phase) and thus release (transfer) heatenergy from the refrigerant to outside the absorption cooling module.See description of FIG. 1 below of absorption cooling module 100.

For the purposes of the present invention, the term “absorptionrefrigerator” refers to a refrigerator used in an absorption coolingmodule which uses heat energy to the drive the cooling process.

For the purposes of the present invention, the term“refrigerant-absorbent mixture” (also referred to interchangeably as the“working fluid”) refers to a coolant fluid which comprises one or morerefrigerants and one or more absorbents which may be used in embodimentsof the absorption cooling modules according to the present invention.The refrigerant-absorbent mixture may be, for example, a homogeneousliquid, a colloidal suspension (e.g., a suspension of absorbentparticles in a liquid refrigerant), etc.

For the purposes of the present invention, the term “absorptionimmersion cooling module” refers to an absorption cooling module whereinat least some of the components of the computer hardware that generateheat energy are immersed in a fluid refrigerant-absorbent mixture.

For the purposes of the present invention, the term “refrigerant” refersto a composition, compound, substance, mixture, etc., which undergoesphase transitions from liquid to gas and back again from gas to liquid.Refrigerants suitable for use herein have boiling points of, forexample, about 135° C. or less, such as in the range of from about −35°to about 130° C., and may include one or more of: dielectricfluorocarbons (e.g., may have at least 3 carbon atoms, such as from 3 to12 carbon atoms, may have an alkane or ether backbone, may have alkoxygroups, may have fluoroalkyl groups, may have at least 5 fluoro groups,such as from 5 to 16 fluoro groups, etc.), including dielectricchlorofluorocarbons (e.g., Freon type), many of the fluorocarbons beingsold/distributed by 3M under the Novec tradename; ammonia, etc. Suitabledielectric fluorocarbons for use herein as refrigerants may have boilingpoints in the range of, for example, from about 15° to about I 30° C.,and may include one or more of: 1,1,1,3,3-pentafluoropropane (known asR-245fa); 1-methoxyheptafluoropropane (known as Novec 7000);perfluoro(2-methyl-3-pentanone) (known as Novec 649 or Novec 1230);nonafluoromethoxybutane (known as Novec 7100);1,1,1,2,2,3,4,5,5,5-decafluoro-3-methoxy-4-(trifluoromethyl)pentane(known as Novec 7300); 2-(trifluoromethyl)-3-ethoxydodecafluorohexane(known as Novec 7500); etc.

For the purposes of the present invention, the term “absorbent” refersto a composition, compound, substance, mixture, etc., which, when mixedwith a refrigerant to form a refrigerant solution, elevates the boiling(volatilization) temperature of refrigerant present in the mixture ascompared to the refrigerant alone. For ammonia-water absorption coolingmodules wherein ammonia is the refrigerant, water may be used as theabsorbent. For absorption immersion cooling modules wherein one or morefluorocarbons are used as the refrigerant, the absorbents may includeone or more of: fluoride salts (such as cesium fluoride); lithiumbromide; N,N-dimethylacetamide (DMCA); N-methyl-2-pyrrolidone (NMP);dimethyl-ethylene urea (DMEU); tetraethylene glycol dimethyl ether(TEGDME); N-methyl E-caprolactum (MCL); functionalized graphene oxidenanoplatelets; etc.

For the purposes of the present invention, the term “capping gas” refersto an inert gas such hydrogen, helium, argon, neon, nitrogen, etc.,which is not miscible with the refrigerant and which allows forequalization of the pressure in a absorption refrigerator module, thusavoiding the need to use an expansion valve for that purpose.

For the purposes of the present invention, the term “graphene” refers topure or relatively pure carbon in the form of a relatively thin, nearlytransparent sheet, which is one atom in thickness (i.e., a monolayersheet of carbon), or comprising multiple layers (multilayer carbonsheets), having a plurality of interconnected hexagonal cells of carbonatoms most of which are present in sp2 hybridized state and which form ahoneycomb like crystalline lattice structure. In addition to hexagonalcells, pentagonal and heptagonal cells (defects), versus hexagonalcells, may also be present in this crystal lattice.

For the purposes of the present invention, the term “graphene oxide”(also known as “graphitic acid” and “graphite oxide”) refersinterchangeably to a compound of carbon, oxygen, and hydrogen which mayexist in variable ratios of these three atoms, and which may be obtainedby treating graphite with strong oxidizers.

For the purposes of the present invention, the term “functionalizedgraphene” refers to graphene which has incorporated into the graphenelattice a variety chemical functional groups such as —OH, —COOH, —NH2,alkyl groups, etc., in order to modify the properties of graphene.

For the purposes of the present invention, the term “partially reducedgraphene oxide” refers to graphene oxide that, upon reduction, containsfrom about 5 about 30% oxygen by weight of the graphene oxide.

For the purposes of the present invention, the term “graphenenanoplatelets (NGPs)” and “nanosheets” refer interchangeably toplatelets of graphene, and may also refer to platelets and sheetscomprised of other graphene-like materials such as graphene oxide,partially reduced graphene oxide, functionalized graphene, etc., havinga thickness in the range of from about 0.34 to about 100 nm and mayinclude one material or in any combination.

For the purposes of the present invention, the term “fluid” refers to acomposition, compound, substance, material, etc., which may be in eithera liquid or gaseous state at the temperature of use (e.g., roomtemperature).

For the purposes of the present invention, the term “liquid” refers to anon-gaseous fluid composition, compound, substance, material, etc.,which may be readily flowable at the temperature of use (e.g., roomtemperature) with little or no tendency to disperse and with arelatively high compressibility.

For the purposes of the present invention, the term “solid” refers tonon-volatile, non-liquid components, compounds, materials, etc., whichmay be in the form of, for example, particulates, particles, powders,etc.

For the purposes of the present invention, the term “room temperature”refers to refers to the commonly accepted meaning of room temperature,i.e., an ambient temperature of from about 20° to about 25° C.

For the purposes of the present invention, the term “comprising” meansvarious compositions, compounds, components, elements, steps, etc., maybe conjointly employed in embodiments of the present invention.Accordingly, the term “comprising” encompasses the more restrictiveterms “consisting essentially of” and “consisting of.”

For the purposes of the present invention, the terms “a” and “an” andsimilar phrases are to be interpreted as “at least one” and “one ormore.” References to “an” embodiment in this disclosure are notnecessarily to the same embodiment.

For the purposes of the present invention, the term “and/or” means thatone or more of the various compositions, compounds, components,elements, steps, etc., may be employed in embodiments of the presentinvention.

Unless otherwise specified, all percentages given herein are by weight.

In this detailed description of the present invention, a person skilledin the art should note that directional terms, such as “above,” “below,”“upper,” “lower,” and other like terms are used for the convenience ofthe reader in reference to the drawings. Also, a person skilled in theart should notice this description may contain other terminology toconvey position, orientation, and direction without departing from theprinciples of the present invention.

Furthermore, in this detailed description, a person skilled in the artshould note that quantitative qualifying terms such as “generally,”“substantially,” “mostly,” and other terms are used, in general, to meanthat the referred to object, characteristic, or quality constitutes amajority of the subject of the reference. The meaning of any of theseterms is dependent upon the context within which it is used, and themeaning may be expressly modified.

Blockchain technologies and related cryptocurrency mining operationsinvolved in bitcoin networks rely heavily on computational work whichconsumes primarily electrical power. In performing a significant amountof computational work, mining farms by necessity consume a substantialamount of electrical power. As blockchain technologies and relatedcryptocurrency mining operations become more prevalent, the total amountof electric power consumed worldwide will likewise grow rapidly. Due tothis significant consumption of electrical power by mining operations,especially mining farms, the blockchain and related cryptocurrencymining industries are becoming one of the largest consumers ofelectrical power, on par with other large energy consuming industriessuch as aluminum production.

The components in computer devices (collectively, the computer hardware)which may used for such mining, including computer processing units(CPUs), graphical processing unit (GPUs), field-programmable gate arrays(FPGAs), etc., as well as stand-alone computer devices such asapplication-specific integrated circuits (ASICs), etc., requireelectrical power to function. This computer hardware used in such miningoperations may consume substantial amounts of electric power. Thus, thecost of the electric power consumed in such mining operations may becomea substantial portion of the final cryptocurrency price.

A significant by-product of such electrical power consumption by suchcomputer hardware used in mining operations is thermal energy (heat).The heat energy generated by the computer hardware used such miningoperations is currently simply dissipated in the surrounding environmentand lost. But given the substantial consumption of electrical power bysuch computer hardware in these mining operations, the total cost ofsuch electrical power consumed, and its potential impact on the cost ofon the desired end-product obtained during such mining operations (e.g.,cryptocurrency), saving or recovering the value of the by-product ofsuch electrical power consumption, namely heat energy, generated by thecomputer hardware in such mining operations is becoming increasinglyimportant.

As blockchain technologies and related cryptocurrency mining operationsinvolved in bitcoin networks further develop and improve, thisspecialized computer hardware used for the mining operation will likelybecome more and more efficient, but is unlikely to solve all of theelectrical energy consumption problems, including heat energy generationof the mining operation. The mining operation is governed in such a waythat regardless of the efficiency of the computer hardware networksupporting the blockchain, the overall system also is likely toautomatically adjust the difficulty level of the problems need to besolved in order to add another record to the blockchain ledger so thatit covers approximately an equal amount of time.

To recoup some of the significant cost of the electric power consumed bythe computer hardware in such mining operations, the heat energygenerated (produced) by the computer hardware used in the miningoperation could be recovered and collected so that it may be used, forexample, in heating homes, swimming pools, green houses, etc. However,such use of the collected heat energy may require specialized equipmentwhich could collect the heat energy from the mining hardware andtransfer it to the point where the heat energy is consumed.

Alternatively, and according to embodiments of the method and system ofthe present invention, the heat energy generated by the computerhardware in the mining operation, could instead be used in for coolingapplications, such air conditioning, food preservation, other types ofrefrigeration, etc. In embodiments of the method and system of thepresent invention, the heat energy generated by the computer hardware inthe mining operation is recovered and then that recovered heat energy isutilized (e.g., transferred) to volatilize a refrigerant for use incooling operations such as such as those described above. The coolingproduced by this method and system can thus compensate for the electricenergy consumption cost of the computer hardware used in the miningoperation supporting the blockchain related cryptocurrency miningoperations involved in bitcoin networks.

General Operation of Absorption Cooling Module. In embodiments of themethod and system of the present invention, the computer hardware usedin the mining operation employs an absorption cooling module to provide,for example, a closed continuous cooling cycle. Referring to FIG. 1 ,such a system is shown schematically, indicated generally as 100, withthe absorption cooling module being indicated generally as 104. Heatenergy (QG) generated by computer hardware 108 is transferred, asindicated by arrow 112, to generator 116 containing an absorptioncoolant fluid in the form of a fluid (e.g., liquid)refrigerant-absorbent mixture.

As further shown in FIG. 1 , the heat energy (QG) 112 transferred fromcomputer hardware 108 to generator 116 causes the refrigerant present inthe fluid refrigerant-absorbent mixture to form refrigerant vapors whichare then transferred, as indicated by arrow 120, to condenser 124. Incondenser 124, some of the heat energy (Qc) is released, as indicated byarrow 128, from the refrigerant vapors, thus converting thoserefrigerant vapors back into a liquid refrigerant. The liquidrefrigerant from condenser 124, as indicated by arrow 128, then passes,as indicated by arrow 132, through expansion valve 136 and, as indicatedby arrow 140, into an evaporator 144. Evaporator 144 vaporizes therefrigerant which absorbs the heat energy (QE), as indicated by arrow148, from the environment, thus producing the cooling effect and formingrefrigerant vapors. The refrigerant vapors from evaporator 144 enter, asindicated by arrow 152, absorber 156 and combine with the absorbent inthe refrigerant-depleted fluid refrigerant-absorbent mixture, asindicated by arrow 160. (This refrigerant-depleted fluidrefrigerant-absorbent mixture 160 is what remains after the formation ofrefrigerant vapors (per arrow 120) in generator 116). When therefrigerant vapors combine with the absorbent in the depleted fluidrefrigerant-absorbent mixture 160, heat energy (QA), as indicated byarrow 164, is released, and a refrigerant-enriched fluidrefrigerant-absorbent mixture is formed in absorber 156. Thisrefrigerant-enriched fluid refrigerant-absorbent mixture from absorber156 is then returned, as indicated by arrow 168, to generator 116.

System 100 involving absorption cooling module 104 described above couldbe configured into a variety of ways depending upon the coolingapplication involved or desired. For example, the cooling effectproduced by absorption cooling module 104 could be utilized for foodstorage. In this case, the coils of evaporator 144 may be mounted on thefreezer chambers. Alternatively, absorption cooling module 104 may beused for cooling the air inside a building for an air conditioningeffect. In this situation, evaporator 144 may be equipped with anappropriate heat exchanger and include duct work for circulating thecooled air inside the building.

As described above, the fluid refrigerant-absorbent mixture m generator116 comprises a mixture of a refrigerant and an absorbent. (As describedbelow with respect to ammonia-water absorption refrigerator module 204,the fluid refrigerant-absorbent mixture may further comprise a cappinggas.) The refrigerant is essentially the active ingredient that achievesthe cooling effect. Suitable fluid refrigerant-absorbent mixtures foruse in generator 116 usually satisfy the following requirements: (a)have a relatively high heat of vaporization as well as a relatively highconcentration of the refrigerant to maximize the cooling benefit (i.e.,the cooling effect of the cooling module provided per unit of mass ofthe refrigerant-absorbent mixture used) in the fluidrefrigerant-absorbent mixture; (b) have a relatively high thermalconductivity in units of watts per meter-Kelvin (W/m K) to providesufficient heat transfer and an appropriate viscosity; and (c) aredesirably non-corrosive to the various components of absorption coolingmodule 104.

The absorbent (which may be a compound, composition, etc.) mixed withthe refrigerant to form the fluid refrigerant-absorbent mixture elevatesthe boiling (volatilization) temperature of the refrigerant present inthe solution compared to the refrigerant alone. These conditions may beachieved if the refrigerant and the absorbent have an affinity to eachother, such as, for example, by forming a complex or compound, and theformation of this complex or compound is accompanied by the release ofheat energy (QA) 164, as described above. In other words, when therefrigerant combines with the absorbent, there is a non-zero enthalpy offormation of this compound or complex achieved, per the followingequation (1):

Ref+Abs↔(Ref·Abs)_(sol) +ΔH _(sol)  (1)

Wherein in equation 1 above, Ref refers to the refrigerant, Abs refersto the absorbent, (Ref·Abs)_(sol) refers to the complex or compoundformed from combining the refrigerant and absorbent and, ΔH_(sol) is theenthalpy of the complex or compound formed. As indicated in equation (1)above, this reaction is normally reversible, i.e., when heat energy isapplied to the fluid refrigerant-absorbent mixture, this compound orcomplex should split up into the absorbent and the refrigerant.

Embodiments of absorption cooling module 104 may be in the form of anammonia-water absorption refrigerator module or an absorption immersioncooling module, as described below.

Ammonia-Water Absorption Refrigerator Modules. In one embodiment ofabsorption cooling module 104 used in the method and system of thepresent invention, the heat energy produced by the computer hardwareused in the mining operation may be used to power an ammonia-waterabsorption refrigerator module. In this embodiment, absorption coolingmodule 104 uses ammonia gas as the refrigerant. Referring to FIG. 2 , asystem, indicated generally as 200, is provided with an ammonia-waterabsorption refrigerator module, indicated generally as 204. As shown inFIG. 2 , absorption refrigerator module 204 includes a refrigeratorindicated generally as 208. A generator 212 contains a mixture ofammonia as the refrigerant and water as the absorbent to provide thefluid refrigerant-absorbent mixture, indicated generally as 216. Whenheat energy is supplied to generator 212, the ammonia gas evaporates(vaporizes) from the fluid refrigerant-absorbent mixture, passingthrough a water separator 220, and entering the condenser, indicatedgenerally as 224, which is equipped with a heat exchanger 228. Incondenser 224, the vaporized ammonia gas is converted into a liquid formand enters the evaporator, indicated generally as 232. In evaporator232, the liquid ammonia is mixed with hydrogen gas which functions as a“capping gas”, i.e. an inert gas that allows for equalization of thepressure in absorption refrigerator module 204 without using anexpansion valve. The presence of the hydrogen gas in the liquid ammoniacauses a drop in the partial vapor pressure of the ammonia such thatevaporation (vaporization) of the ammonia imparts a cooling effect. Thevaporized ammonia is then mixed with the depleted ammonia-absorbentsolution in an absorber, indicated generally by 236, to provide anammonia-enriched fluid refrigerant-absorbent mixture. Theammonia-enriched fluid refrigerant-absorbent mixture is collected, asindicated generally by 240, in an absorber vessel 244. Theammonia-enriched fluid refrigerant-absorbent mixture 240 in absorbervessel 244 is then returned via a return line 248 to generator 212 toprovide fluid refrigerant-absorbent mixture 216, thus closing the loopfor absorption refrigerator module 204.

As further shown in FIG. 2 , the heat energy provided to absorptionrefrigerator module 204 is obtained from computer hardware, indicatedgenerally as 252, from a blockchain mining operation. In one embodimentof system 200, circuit boards such as printed circuit boards (PCBs),three of which are shown and are indicated as 256-1 through 256-3, ofcomputer hardware 252 may be mounted directly to generator 212.Provisions may be made to ensure that there is proper thermal contactbetween the computer chips mounted on PCBs 256-1 through 256-3 and thebody of generator 212. The rate of the heat energy generation by PCBs256-1 through 256-3 may also be controlled by adjusting thecomputational speed.

As shown in FIG. 2 , in one embodiment of absorption refrigerator module204, the heat energy generated by PCBs 256-1 through 256-3 of computerhardware 252 from the mining operation may be transferred to generator212 by means of a circulating heat transfer fluid. In this embodiment,the computer chips of PCBs 256-1 through 256-3 may be equipped with heatsinks 260, one of which is specifically indicated as 260-3. Heat sinks260 may be made of, for example, copper or aluminum alloy. Heat sinks260 are shown in FIG. 2 as being interconnected, for example, by tubing,indicated generally as 264. Heat transfer fluid (not shown) passesthrough the internal channels (not shown) formed in heat sinks 260. Ifthe heat transfer fluid is present for sufficient time inside heat sinks260, the temperature of the heat transfer fluid within will be at theequilibrium with that of heat sinks 260. The heated fluid within heatsinks 260 is then circulated by a fluid pump 268, and is then passedthrough a heat exchanger, indicated generally as 272, mounted ongenerator 212.

In an alternative embodiment of absorption cooling module 204, heatgenerated by PCBs 256-1 through 256-3 of computer hardware 252 of themining operation may, instead, be transferred to the generator 212through the use of one or more thermally conductive foils made fromgraphene nanoplatelets which are connected from PCBs 256-1 through 256-3to the generator. The graphene foil may be manufactured, for example, byrolling out graphene nanoplatelets as relatively thin sheets having athickness in the range of from about 10 to about 50 μm. Such graphenefoil may have a lateral thermal conductivity in the range of from about1300 to about 1500 watts per meter-Kelvin (W/m-K). The graphene foil maybe mounted on the computer chips for example with thermally conductiveadhesive.

Absorption Immersion Cooling Module. In another embodiment, absorptioncooling module 100 may be in the form of an absorption immersion coolingmodule to transfer heat energy from the computer hardware used in themining operation. See U.S. Pat. No. 4,704,658 (Yokouchi et al.) issuedNov. 3, 1987, the entire disclosure and contents of which are hereinincorporated by reference, which discloses an immersion cooling modulefor semiconductor devices. In an absorption immersion cooling module,the computer hardware used in the mining operation is placed within avessel filled with an absorption coolant fluid. The components (e.g.,PCBs) of the computer hardware from mining operation are mounted invessel and are immersed in the coolant fluid. The vessel is alsoequipped with a condenser. The heat energy generated by these componentsof the computer hardware immersed in the coolant fluid cause boiling(vaporization) of the refrigerant present in the coolant fluid. Thecondenser, which may also include a heat sink with a fin stock that iscooled by, for example, water supplied from outside the condenser,condenses the refrigerant vapors of the coolant fluid and converts thosevapors back into a liquid form which are then returned to the coolantfluid in the vessel.

One embodiment of such a system using an absorption immersion coolingmodule according to the present invention is shown in FIG. 3 . Referringto FIG. 3 , a system, indicated generally as 300, is provided with anabsorption immersion cooling module, indicated generally as 304. Inabsorption immersion cooling module 304, the immersion tank, indicatedgenerally as 308, is filled with a fluid refrigerant-absorbent mixture,indicated by arrow 312, which comprises a mixture of the refrigerant andabsorbent. The refrigerant may any of a number of immersion dielectricrefrigerants, such as fluorocarbons.

Components of the computer hardware used in the mining operation,indicated generally as 316, are mounted within (inside) tank 308 and areimmersed in the fluid refrigerant-absorbent mixture 312. Heat energy(QG), indicated by arrow 320, generated by components 316 of thecomputer hardware causes evaporation (vaporization) of the refrigerantin the fluid refrigerant-absorbent mixture 312 in tank 308. Tank 308 maybe hermetically sealed such that the refrigerant vapors generated intank 308 may be collected and transmitted to the condenser, as indicatedgenerally as 324. In condenser 324, the refrigerant vapors are convertedback into a liquid refrigerant. The heat energy (Qc), indicated by arrow328 released during this conversion of refrigerant vapors back to aliquid refrigerant may be released into the outside environment,especially when condenser 324 is mounted outside of the building wherethe mining operation takes place.

The liquid refrigerant formed in condenser 324 passes through anexpansion valve 332 and into an evaporator, indicated generally as 336.Inside evaporator 336, evaporation (vaporization) of the liquidrefrigerant again occurs; thus causing a cooling effect. Heat energy(QE), indicated by arrow 340, required for such evaporation of theliquid refrigerant is thus released and removed from the environment.For practical reasons, evaporator 336 may be equipped with heatexchangers, ventilation ducts, blower fans, etc., or may be mounted ontoa refrigeration chamber depending upon the cooling effect to beachieved. In an alternative embodiment of an absorption immersioncooling module 304, the refrigerant which evaporates (vaporizes) insideevaporator 336 may be mixed with a capping gas, such as hydrogen,helium, etc. Mixing the refrigerant with this capping gas causes a dropin the partial pressure of the refrigerant vapors, thus imparting a morerapid evaporation (vaporization) of the liquid refrigerant and thus afaster cooling effect. The use of the capping gas also equalizes thetotal pressure inside absorption immersion cooling module 304.

The refrigerant vapors from evaporator 336 are then admitted to anabsorber, indicated generally as 344, wherein the refrigerant vapors aremixed with the depleted fluid refrigerant-absorbent mixture, indicatedgenerally as 348, which is provided to absorber 344, via line 352, by afirst (electric) pump 356, from tank 308 to form a refrigerant-enrichedfluid refrigerant-absorbent mixture. A sprayer assembly, indicatedgenerally as 364, may also be installed in absorber 344 to furtherenhance the absorption of the refrigerant vapors by the depleted fluidrefrigerant-absorbent mixture in forming the refrigerant-enriched fluidrefrigerant-absorbent mixture. In absorber 344, the refrigerant absorbedby the depleted fluid refrigerant-absorbent mixture in forming therefrigerant-enriched fluid refrigerant-absorbent mixture is accompaniedby a release of heat energy (QA), indicated by arrow 360. Therefrigerant-enriched fluid refrigerant-absorbent mixture may then betransferred from absorber 344 via return line 368 by second (electric)pump 372.

Several suitable immersion refrigerants for use in absorption immersioncooling module 304 (under the Novec tradename from 3M) and theirproperties are show in the following Table 1:

TABLE 1 Boiling Point Name Trade Name CAS number (° C.) FIG.1-Methoxyheptafluoro- Novec 7000 375-03-1 34 401 propanePerfluoro(2-methyl-3- Novec 649 756-13-8 49 402 pentanone)Nonafluoromethoxybutane Novec 7100 163702-08-7 61 403 Tetradecafluoro-2-Novec 774 7379-12-6 74 — methylhexan-3-one I,1,1,2,2,3,4,5,5,5- Novec7300 132182-92-4 98 405 Decafluoro-3-methoxy-4- (trifluoromethyl)pentane2-(Trifluoromethyl)-3- Novec 7500 297730-93-9 128 406ethoxydodecafluorohexane

As mentioned above, the absorbent used in any of the absorption coolingmodules shown in FIGS. 1 through 3 need to satisfy several requirements:(a) have a high vapor pressure; (b) be a dielectric; and (c) when mixedwith the refrigerant, form a solution accompanied by a release of heatenergy. There several potential compounds or compositions which may beused as absorbents. For example, certain fluoride salts may be used asan absorbent in the absorption immersion cooling module 304 describedherein. See Evans et al., “Formation of Adducts Between FluorinatedKetones and Metal Fluorides,” The Journal of Organic Chemistry, Vol.33(5), (1968), pp. 1837-1839, the entire disclosure and contents ofwhich are herein incorporated by reference, which discloses certainfluoride salts which can form an adduct with certain fluorinatedketones, as well as the heat energy which can generated by such adductformation. An example of a fluoride salt suitable for use herein as anabsorbent for fluorocarbon refrigerants is cesium fluoride. Cesiumfluoride has a low lattice energy and may form an adduct withfluorinated ketones.

Yet another metal salt for suitable use herein as an absorbent forfluorocarbon refrigerants is lithium bromide. In utilizing such metalsalts such as lithium bromide as absorbents for fluorocarbonrefrigerants used in fluid refrigerant-absorbent mixture in absorptionimmersion cooling modules 304 s, care may need to be taken with suchmetal salts as fluid refrigerant-absorbent mixtures containing same maycause the coolant fluid to become corrosive and to cause degradation ofthe computer hardware used in the mining operation.

Additional suitable absorbents for use herein include DMCA(N,N-dimethylacetamide), NMP (N-methyl-2-pyrrolidone), DMEU(dimethyl-ethyleneurea), TEGDME (tetraethylene glycol dimethyl ether),and MCL (N-methyl E-caprolactum). See Sun et al., “A Review of WorkingFluids of Absorption Cycles,” Renewable and Sustainable Energy Reviews,Vol. 16 (2012), pp. 1899-1906. As described in the Sun et al. article,these compounds may also be successfully employed as absorbents withhalogenated hydrocarbons. Accordingly, these compounds may be used asabsorbents with the above-mentioned immersion fluids employed asrefrigerants.

Properly functionalized graphene oxide nanoplatelets may also serve asan absorbent. Functionalized graphene oxide suitable for use herein asan absorbent comprises a hydrophilic molecule having polaroxygen-containing functional groups (e.g., carboxyl-, hydroxyl-,carbonyl-, epoxy-, etc.). These graphene oxide nanoplatelets have arelatively large specific surface area (e.g., a few hundred m2/g.),which is an important property for use as a solid absorbent. Becausethese graphene oxide nanoplatelets are heavily functionalized, they arealso not electrically conductive, i.e., are dielectric. Appropriatechemical modification of these functionalized graphene oxidenanoplatelets may also significantly increase their dispersibility innon-polar organic solvents, including the perfluorinated refrigerantsdescribed above. One such chemical modification of the graphene oxidesurface may be by including, for example, one or more alkyl substituentgroups having a chain length of from 7 to 14 carbon atoms. By employingsuch chemical modification, the functionalized polar groups of themodified graphene oxide nanoplatelets may adhere more effectively to themolecules of the immersion refrigerant by specific hydrogen bonding andnon-specific electrostatic interaction to form a complex having anegative enthalpy. Such a modified functionalized graphene oxidenanoplatelets may raise the boiling (vaporization) point of theimmersion refrigerant, thereby satisfying the requirements for anabsorbent. Thus, such modified functionalized graphene oxidenanoplatelets may provide an effective absorbent when combined with therefrigerant in a refrigerant solution for absorption immersion coolingmodule 304, as described above.

All documents, patents, journal articles and other materials cited inthe present application are hereby incorporated by reference.

Although the present invention has been fully described in conjunctionwith several embodiments thereof with reference to the accompanyingdrawings, it is to be understood that various changes and modificationsmay be apparent to those skilled in the art. Such changes andmodifications are to be understood as included within the scope of thepresent invention as defined by the appended claims, unless they departtherefrom.

In addition, the purpose of the Abstract of the Disclosure in thisapplication is to enable the U.S. Patent and Trademark Office, as wellas the public generally, including any scientists, engineers andpractitioners in the art who may not be familiar with patent or otherlegal terms or phraseology to determine the what the technicaldisclosure of the application describes. Accordingly, while the Abstractof the Disclosure may be used to provide enablement for the followingclaims, it is not intended to be limiting as to the scope of thoseclaims in any way.

Finally, it is the applicant's intent that only claims which include theexpress language “means for” or “step for” be interpreted under 35U.S.C. § 112, paragraph 6. Accordingly, claims that do not expresslyinclude the phrase “means for” or “step for” are not to be interpretedas being within the purview of 35 U.S.C. § 112, paragraph 6, or to beconstrued as being subject to any case law interpreting the meaning ofthese phrases.

Some of the illustrative aspects of the present invention may beadvantageous in solving the problems herein described and other problemsnot discussed which are discoverable by a skilled artisan.

While the above description contains much specificity, these should notbe construed as limitations on the scope of any embodiment, but asexemplifications of the presented embodiments thereof. Many otherramifications and variations are possible within the teachings of thevarious embodiments. While the invention has been described withreference to exemplary embodiments, it will be understood by thoseskilled in the art that various changes may be made and equivalents maybe substituted for elements thereof without departing from the scope ofthe invention. In addition, many modifications may be made to adapt aparticular situation or material to the teachings of the inventionwithout departing from the essential scope thereof. Therefore, it isintended that the invention not be limited to the particular embodimentdisclosed as the best or only mode contemplated for carrying out thisinvention, but that the invention will include all embodiments fallingwithin the scope of the appended claims. Also, in the drawings and thedescription, there have been disclosed exemplary embodiments of theinvention and, although specific terms may have been employed, they areunless otherwise stated used in a generic and descriptive sense only andnot for purposes of limitation, the scope of the invention therefore notbeing so limited. Moreover, the use of the terms first, second, etc. donot denote any order or importance, but rather the terms first, second,etc. are used to distinguish one element from another. Furthermore, theuse of the terms a, an, etc. do not denote a limitation of quantity, butrather denote the presence of at least one of the referenced item.

Thus the scope of the invention should be determined by the appendedclaims and their legal equivalents, and not by the examples given.

The claims in the instant application are different than those of theparent application or other related applications. Applicant thereforerescinds any disclaimer of claim scope made in the parent application orany predecessor application in relation to the instant application. Anysuch previous disclaimer and the cited references that it was made toavoid, may need to be revisited. Further, any disclaimer made in theinstant application should not be read into or against the parentapplication.

What is claimed is:
 1. A method for recovering heat energy from computerhardware in a blockchain mining operation, the method comprising thesteps of: providing heat energy generated by the computer hardware in ablockchain mining operation; and utilizing the heat energy in anabsorption cooling module to generate a cooling effect with a coolantfluid comprising a fluid refrigerant-absorbent mixture; wherein theabsorption cooling module comprises: an ammonia-water absorptionrefrigerator module having a generator configured to absorb heat energyadjacent to the generator; at least one heatsink positioned on thecomputer hardware; a fluid pump in fluid communication with the at leastone heatsink; and a heat exchanger in fluid communication with the fluidpump and the at least one heatsink; wherein at least a portion of theheat exchanger is at least adjacent to the generator; wherein the fluidpump circulates a heat transfer fluid to and from the at least oneheatsink and the heat exchanger; wherein the heat transfer fluid absorbsheat energy from the at least one heatsink and the computer hardware;and wherein the generator absorbs heat energy from the heat exchangerand the heat transfer fluid.
 2. The method of claim 1, wherein theblockchain mining operation is at least one of a cryptocurrency miningoperation and a mining farm.
 3. The method of claim 1, wherein the fluidrefrigerant-absorbent mixture comprises ammonia as the refrigerant andat least one of water and a fluoride salt as the absorbent.
 4. Themethod of claim 1, wherein the absorbent of the fluidrefrigerant-absorbent mixture comprises functionalized graphene oxidenanoplatelets; wherein the functionalized graphene oxide nanoplateletshave one or more polar oxygen-containing functional groups selected fromthe group consisting of: carboxyl, hydroxyl, carbonyl, and epoxy; andwherein the functionalized graphene oxide nanoplatelets are modified tohave one or more alkyl substituent groups having a chain length of from7 to 14 carbon atoms.
 5. The method of claim 1, wherein the computerhardware comprises at least one printed circuit board.
 6. The method ofclaim 1, wherein the at least one heatsink comprises a thermallyconductive foil mounted to the computer hardware by thermally conductiveadhesive, and wherein the thermally conductive foil comprises graphenenanoplatelets.
 7. The method of claim 6, wherein the thermallyconductive foil has a lateral thermal conductivity range of from about1300 to about 1500 Watts per meter-Kelvin.
 8. A system for recoveringheat energy from computer hardware in a blockchain mining operation, thesystem comprising: an absorption cooling module to generate a coolingeffect with a coolant fluid comprising a fluid refrigerant-absorbentmixture; at least one computer hardware that generates heat energy;providing heat energy generated by the computer hardware in a blockchainmining operation; wherein the absorption cooling module comprises: anammonia-water absorption refrigerator module having a generatorconfigured to absorb heat energy adjacent to the generator; at least oneheatsink positioned on the computer hardware; a fluid pump in fluidcommunication with the at least one heatsink; and a heat exchanger influid communication with the fluid pump and the at least one heatsink;wherein at least a portion of the heat exchanger is at least adjacent tothe generator; wherein the fluid pump circulates a heat transfer fluidto and from the at least one heatsink and the heat exchanger; whereinthe heat transfer fluid absorbs heat energy from the at least oneheatsink and the computer hardware; and wherein the generator absorbsheat energy from the heat exchanger and the heat transfer fluid.
 9. Thesystem of claim 11, wherein the blockchain mining operation is at leastone of a cryptocurrency mining operation and a mining farm.
 10. Thesystem of claim 11, wherein the fluid refrigerant-absorbent mixturecomprises ammonia as the refrigerant and at least one of water and afluoride salt as the absorbent.
 11. The system of claim 11, wherein theabsorbent of the fluid refrigerant-adsorbent mixture comprisesfunctionalized graphene oxide nanoplatelets, wherein the functionalizedgraphene oxide nanoplatelets have one or more polar oxygen-containingfunctional groups selected from the group consisting of: carboxyl,hydroxyl, carbonyl, and epoxy; and wherein the functionalized grapheneoxide nanoplatelets are modified to have one or more alkyl substituentgroups having a chain length of from 7 to 14 carbon atoms.
 12. Thesystem of claim 11, wherein the at least one heatsink comprises athermally conductive foil mounted to the computer hardware by thermallyconductive adhesive, and wherein the thermally conductive foil comprisesgraphene nanoplatelets.
 13. The system of claim 12, wherein thethermally conductive foil has a lateral thermal conductivity range offrom about 1300 to about 1500 Watts per meter-Kelvin.
 14. The system ofclaim 11, further comprising adjusting computational speeds of thecomputer hardware to control a rate of heat energy generated by thecomputer hardware.
 15. A system for recovering heat energy from computerhardware in a blockchain mining operation, the system comprising: anabsorption cooling module to generate a cooling effect with a coolantfluid comprising a fluid refrigerant-absorbent mixture; at least onecomputer hardware that generates heat energy; providing heat energygenerated by the computer hardware in a blockchain mining operation;wherein the absorption cooling module comprises: an ammonia-waterabsorption refrigerator module having a generator configured to absorbheat energy adjacent to the generator, wherein the ammonia-waterabsorption refrigerator module utilizes a fluid refrigerant-absorbentmixture; at least one heatsink comprising a thermally conductive foilmounted to the computer hardware by thermally conductive adhesive,wherein the thermally conductive foil comprises graphene nanoplatelets;a fluid pump in fluid communication with the at least one heatsink; anda heat exchanger in fluid communication with the fluid pump and the atleast one heatsink; wherein at least a portion of the heat exchanger isat least adjacent to the generator; wherein the fluid pump circulates aheat transfer fluid to and from the at least one heatsink and the heatexchanger; wherein the heat transfer fluid absorbs heat energy from theat least one heatsink and the computer hardware; and wherein thegenerator absorbs heat energy from the heat exchanger and the heattransfer fluid.
 16. The system of claim 15, wherein the adsorbent of thefluid refrigerant-adsorbent mixture comprises at least one of a fluoridesalt and functionalized graphene oxide nanoplatelets.
 17. The system ofclaim 15, wherein the absorbent of the fluid refrigerant-adsorbentmixture comprises functionalized graphene oxide nanoplatelets, whereinthe functionalized graphene oxide nanoplatelets have one or more polaroxygen-containing functional groups selected from the group consistingof: carboxyl, hydroxyl, carbonyl, and epoxy; and wherein thefunctionalized graphene oxide nanoplatelets are modified to have one ormore alkyl substituent groups having a chain length of from 7 to 14carbon atoms.
 18. The system of claim 15, wherein the thermallyconductive foil has a lateral thermal conductivity range of from about1300 to about 1500 Watts per meter-Kelvin.
 19. The system of claim 15,wherein the blockchain mining operation is at least one of acryptocurrency mining operation and a mining farm.
 20. The system ofclaim 15, wherein the refrigerant of the liquid refrigerant-adsorbentmixture comprises ammonia.